Mixers for fluids, e.g. gases, are known. Air mixers with air flow controlling means are known. For example, U.S. Pat. No. 3,405,758 to Walker et al., which issued Oct. 15, 1968, discloses mixing fresh air and recirculating air in a mixing chamber. The two air flows are controlled by two dampers, which operate such that when one damper opens the other damper closes. U.S. Pat. No. 4,352,321 to Fukui et al. which issued Oct. 5, 1982, discloses an automobile air conditioning system in which outside air and recirculated air may be directed into the automobile by moving a simple gate across openings from side by side outside and recirculating air ducts. PCT application FI88/00151 to C. Palander, published on Apr. 6, 1989 under WO89/03006, discloses an air conditioning apparatus with a mixing chamber for cold and warm air. It has a gate for adjusting the relative amounts of cold air or warm air passing through the air inlets. U.S. Pat. No. 5,368,521 to R. P. Koenig, which issued Nov. 29, 1994 discloses a fluid distributor for stratified mixing of air streams. None of these mixers are particularly efficient at mixing the two air streams. The present invention is directed to overcoming the deficiencies of prior systems.
The terms "comprising/comprises" when used in this specification are taken to specify the presence of the stated features, integers, steps or components but do not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.